This study investigated the dosing patterns for aripiprazole augmentation for major depressive disorder (MDD) in a naturalistic treatment setting. Between 1 January 2009 and 31 March 2012, patients with a diagnosis of MDD who were receiving aripiprazole augmentation in conjunction with an ongoing antidepressant were recruited for this study. The electronic medical records and clinical data for a total of 276 patients were reviewed up to a year. The mean duration of aripiprazole augmentation was ∼5 months; the mean time to the first increase of aripiprazole was about 3 weeks; and the mean initial, first up-titrated, maximal, and maintenance doses were 3.4, 4.2, 4.7, and 4.4 mg/day, respectively. The most frequent adverse events were insomnia, followed by anxiety and sedation. The current results indicate that the actual doses of aripiprazole augmentation with ongoing antidepressant for MDD should be lower than the doses used in placebo-controlled clinical trials and those recommended by the US Food and Drug Administration. Adequately powered and well-controlled prospective studies are needed to better understand the exact role of low doses of aripiprazole augmentation in the treatment of MDD, particularly in routine practice.